Irrigation Controller With Removable Station Modules

ABSTRACT

An irrigation controller includes a housing for enclosing a microprocessor that stores and executes at least one watering program. The microprocessor has a parallel output bus with a plurality of pin sets for controlling a plurality of irrigation stations. The connection between the controller and the irrigation stations is through a plurality of station modules that are removably coupled, in any desired number, to the various pin sets on the output bus. The number of stations controlled is adjusted by the number of modules connected to the output bus. The controller housing has a pocket for holding a user&#39;s manual, which is positioned between the controller housing and a mounting bracket. when the controller housing is installed on the mounting bracket.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/332,158 filed Dec. 20, 2011 entitled Irrigation Controller WithRemovable Station Modules, which is a continuation of U.S. patentapplication Ser. No. 13/016,844 filed Jan. 28, 2011 entitled IrrigationController With Removable Station Modules (now abandoned), which is acontinuation of U.S. patent application Ser. No. 12/760,356 filed Apr.14, 2010 entitled Irrigation Controller With Removable Station Modules(now abandoned), which is a continuation of U.S. patent application Ser.No. 12/023,972 filed Jan. 31, 2008 entitled Irrigation Controller WithRemovable Station Modules (now abandoned), which is a continuation ofU.S. patent application Ser. No. 11/282,454 filed Nov. 17, 2005 entitledIrrigation Controller With Removable Station Modules (now abandoned),which is a continuation of U.S. patent application Ser. No. 10/887,367filed Jul. 6, 2004 entitled Irrigation Controller With Removable StationModules (now U.S. Pat. No. 6,996,457 issued Feb. 7, 2006), which is acontinuation of U.S. patent application Ser. No. 10/198,849 filed Jul.19, 2002 entitled Irrigation Controller With Removable Station Modules(now U.S. Pat. No. 6,772,050 issued Aug. 3, 2004), which is acontinuation of U.S. patent application Ser. No. 09/400,031 filed Sep.21, 1999 entitled Irrigation Controller With Removable Station Modules(now U.S. Pat. No. 6,459,959 issued Oct. 1, 2002), which is acontinuation of U.S. patent application Ser. No. 08/904,125 filed Jul.28, 1997 entitled Irrigation Controller With Removable Station Modules(now U.S. Pat. No. 5,956,248 issued Sep. 21, 1999), which is acontinuation of U.S. patent application Ser. No. 08/312,268 filed Sep.23, 1994 entitled Irrigation Controller With Removable Station Modules(now abandoned), all of which are incorporated herein by reference intheir entireties.

TECHNICAL FIELD

This invention relates to an irrigation controller for controlling theoperation of an irrigation system pursuant to a watering schedule thatmay be programmed by the user. More particularly, this invention relatesto an irrigation controller for controlling multiple irrigationstations.

BACKGROUND OF THE INVENTION

Irrigation controllers are known for controlling the operation of anirrigation system in accordance with the passage of time. Mostcontrollers operate a plurality of watering stations and will retain orstore a watering program established by the user. This program typicallyallows the user to pick what days the sprinklers will operate, what timeof day that irrigation will begin, and how long each station willoperate. Some controllers allow multiple watering programs to be stored.

U.S. Pat. No. 5,262,936 discloses a microprocessor based controller inwhich the controller base unit has drivers and switches for controllingsome number of irrigation stations that is less than the maximum numberthat can be controlled. The station handling ability of the controllercan be expanded by plugging in additional modules with each modulehaving drivers and switches for an additional number of stations. Themodules when connected extend and are part of a serial bus structure inthe controller. The modules known in this prior controller are quitelarge and when connected to the base unit of the controller take upconsiderable space exteriorly of the base unit, leading to problems infinding sufficient space to receive them all and in attaching all of themodules in a secure fashion.

SUMMARY OF THE INVENTION

This invention relates to an irrigation controller which comprises ahousing having microprocessor means for storing and executing a wateringprogram for controlling a plurality of irrigation stations. Themicroprocessor means includes a parallel output bus within the housinghaving a plurality of separate station output pins for controlling theirrigation stations with one station output pin used for controllingeach station. At least one module is removably plugged into at least oneof the station output pins on the output bus. The module has a terminalsuited for receiving an electrical lead wire extending to the irrigationstation, and further has driver and switch means for activating thestation as commanded by the base unit over the at least one stationoutput pin.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be described in more detail in the followingDetailed Description, taken in conjunction with the following drawings,in which like reference numerals refer to like elements throughout.

FIG. 1 is a front elevational view of an improved irrigation controlleraccording to this invention, particularly illustrating the controllerhousing and front panel with its associated controls and displays andhaving a portion of the controller broken away to illustrate one of theremovable station modules installed inside the controller housing;

FIG. 2 is a side elevational view of the controller shown in FIG. 1,particularly illustrating the controller housing and its attachment to amounting bracket on which the controller housing is removably installed;

FIG. 3 is a top plan view of the controller shown in FIG. 1,particularly illustrating the controller housing and its mountingbracket;

FIG. 4 is a bottom plan view of the controller shown in FIG. 1 with thecontroller housing in place on its mounting bracket;

FIG. 5 is an exploded, rear elevational view of the controller shown inFIG. 1, particularly illustrating the controller housing detached fromthe mounting bracket and the pocket provided on the back of thecontroller housing for holding a user manual for the controller;

FIG. 6 is an enlarged front elevational view of one of the stationmodules of the controller with the module shown installed in thecontroller of FIG. 1;

FIG. 7 is a cross-sectional view taken along lines 7-7 of FIG. 6,particularly illustrating how the station module is installed in thecontroller of FIG. 1;

FIG. 8 is a partial front elevational view of the controller shown inFIG. 1, with the terminal strip cover being removed to show two stationmodules for controlling four irrigation stations and the rain sensor, 24V AC and pump and common outputs contained on the terminal strip; andFIG. 9 is a schematic diagram of one of the station modules used in thecontroller of FIG. 1.

DETAILED DESCRIPTION

This invention relates to an irrigation controller 2 for controlling theoperation of an irrigation system in a timed manner. More specifically,controller 2 allows the user to select or input at least one wateringprogram comprising the following parameters of irrigation systemoperation:

-   -   which days the sprinklers will operate in a particular 7 day        window (i.e. a calendar sequence) or the interval between        successive operational days up to a maximum interval of 7 days        (i.e. an interval sequence), the operational days being known as        “active days”;    -   when the sprinklers come on during the active days, known as the        “start times”, with up to four start times being selectable; and    -   how long the sprinklers will run after each start, known as the        “run times”.

Controller 2 is adapted to control a plurality of separate watering“stations” in the irrigation system. Each station comprises one or moresprinklers grouped together to operate simultaneously off the sameirrigation valve V. Each irrigation valve V includes an actuator, suchas an electrical solenoid S, which is operated by a control signal fromcontroller 2 to turn valve V on.

Controller 2 of this invention can be easily adapted to controldifferent numbers of stations up to a total of eight stations. A fourstation controller 2 is illustrated in this application. Referring toFIG. 8, the four stations are illustrated by the four separateirrigation valves V1, V2, V3 and V4 wired to controller 2. There will besix irrigation valves V1-V6 wired to controller 2 in a six stationcontroller, eight valves V1-V8 in an eight station controller, and soon. While eight is the maximum number of stations that can be controlledby controller 2 shown herein, the maximum number of stations canobviously be adjusted to a larger number if so desired.

For each watering program stored in controller 2, a run time may be setindividually for each separate station, i.e. different stations may havedifferent run times depending on operator preference. However, theselections of active days and start times apply to all stations as agroup within each watering program. Thus, when an active day and starttime is reached when executing a particular watering program, controller2 will operate the irrigation system by sequencing through the stationsand operating each station for the run time which has been set for thatstation on that particular program. Sequential operation of the stationsis preferred to decrease the demands on the water delivery capacity ofthe irrigation system.

Controller 2 incorporates a microprocessor (not shown) of any suitabledesign which comprises a timing, memory, logic and control means. Themicroprocessor monitors the passage of time and executes whateverwatering program has been input and selected by the user for execution.Operational flexibility is achieved by allowing controller 2 to storeand execute multiple watering programs so that a different combinationof active days, start times, and run times can be stored in differentprograms if so desired. The microprocessor can also permanently store adefault watering program for use if the user fails to input a customizedwatering program or programs of the user's own design.

Typical irrigation controllers based on the use of microprocessors aredisclosed in U.S. Pat. Nos. 5,262,936 and 5,272,620, owned by theassignee of this application. These patents are hereby incorporated byreference.

Referring to FIG. 1, the electronic components of controller 2,including the microprocessor, are contained within a housing 4 of anysuitable design. As will be described in more detail hereafter, housing4 may be mounted on a wall 5 using a mounting bracket 6. Housing 4includes a front panel 8 having various operational controls which maybe manipulated by the user to activate control functions of controller 2or to input information into controller 2. In addition, controller 2includes a display device 10 for displaying information to the user.

The operational controls of controller 2 include a rotary knob or dial12 for selecting various ones of the programmable parameters that can beinput and stored in a watering program, and various push button controlsidentified generally as 14. Push button controls 14 include “up/down” or“plus/minus” keys 14 a, 14 b for incrementing or decrementing the valueof a particular parameter when programming the controller, an “enter”key 14 c for accepting a particular value of a parameter and forproceeding to the next step in the programming sequence, and an “escape”key 14 d to start over during programming. Thus, by rotating dial 12 toa particular position corresponding to a particular parameter that canbe input, the user can then manipulate controls 14 to input and storevalues for the selected parameter while observing in display device 10the values as they are being input for that parameter through theoperation of controls 14.

The type of watering program stored in controller 2, namely the numberand nature of the parameters that can be set and stored in a wateringprogram and then executed by controller 2, can obviously be varied. Inaddition, the nature of the operational controls 12, 14 used to inputthe watering program or access the features of controller 2 can alsoobviously be changed. This invention relates to other features ofcontroller 2, to be described in detail hereafter, that can be usedgenerally on any irrigation controller that controls a plurality ofstations, without being limited to controller 2 as shown herein.

A lower portion of controller 2 houses an input/output terminal area,identified generally as 16, behind an easily removable access strip orpanel 18. Panel 18 is configured to snap onto and off of controllerhousing 4 using known tab and slot connections. Terminal area 16includes space for three, terminal blocks 20 a, 20 b, and 20 c which arehardwired into place. In addition, terminal area 16 includes space forup to four, two-station modules 22 a, 22 b, etc. that are used toconnect controller 2 to the irrigation stations comprising valves V.Station modules 22 are generally identical to one another and are easilyremovable from controller 2—modules 22 simply plug into controller 2 andcan be easily unplugged from controller 2 in a manner to be describedshortly.

Terminal blocks 20 and station modules 22 each have two snap-in wireterminals 24 a, 24 b therein for receiving two connecting wires. Suchterminals are well known in the electrical connection art. They eachhave a pivotal lever 26 that may be rotated 90° from an open position(where lever 26 is vertical and the wire may be inserted into theterminal) to a generally closed position (where lever 26 is horizontaland the wire is clamped or retained in the terminal). The use of suchsnap-in wire terminals is preferred as it eases the task of connectingthe necessary wires to controller 2. Other quick coupling devices couldbe used, or conventional screw type terminals could be used, in place ofsnap-in terminals 24 a, 24 b.

The nature of the wires that are connected to the various terminalblocks 20 and station modules 22 will vary. For example, the firstterminal block 20 a connects to the two lead wires of a rain switch (notshown) which determines if it is raining and allows controller 2 tocease operation in the case of rain. A typical rain switch of the typewhich may be connected to terminal block 20 a is described in U.S. Pat.No. 5,101,083, which is hereby incorporated by reference. An on/offswitch 28 can be mounted in terminal area 16 immediately above terminalblock 20 a for the rain switch. In the off position of switch 28, therain switch input is ignored by controller 2 such that the detection ofrain will not affect the operation of controller 2 or the irrigationsystem.

The second terminal block 20 b is used for the convenient connection ofan external electrical transformer 30 used to provide AC power tocontroller 2. Transformer 30 will be wired or plugged into a standard ACpower source such as 120V AC power, and will provide 24V AC power tocontroller 2. Ultimately, such 24V AC power will be used to activatesolenoids S on irrigation valves V. Additionally, such power can berouted through one of the terminals in terminal block 20 c to activate asolenoid S on a master valve or a relay on an irrigation pump. This isrequired in irrigation systems where a source of pressurized water isnot continually present upstream of valves V, but is provided only whenirrigation is to take place. In this event, either a master valvesupplying valves V must first be opened, or a pump started, to ensuresupply of pressurized water to valves V.

The third terminal block 20 c as noted above uses one of the snap-interminals, namely terminal 24 a, as a master valve or pump relay outputfor supplying 24V AC power from controller 2 to these components. Theother terminal 24 b in terminal block 20 c is used as a common wireconnection COM to ground. Thus, all of the common wires for all of theirrigation valves V may be spliced together, as shown in FIG. 8, andconnected to ground using the common wire terminal 24 b in terminalblock 20 c. In addition, when operating a master valve or pump, thecommon wire for such master valve or pump may also be spliced into andconnected to the common wire connection COM leading to common wireterminal 24 b.

Station modules 22 are used to allow controller 2 to control a desirednumber of stations determined by the number of modules 22 that areinstalled. Each module 22 has two snap-in terminals 24 a, 24 b forcontrolling two stations, with each terminal being connected to thenon-common wire lead from a solenoid S. A module 22 could be used tocontrol only one station if only of the snap-in wire terminals 24 a, 24b is connected to a single solenoid. However, if both terminals arebeing utilized, then each module 22 will control two stations, i.e. twoof the irrigation valves V. See FIG. 8.

Controller 2 is provided with means for accepting up to a predeterminedmaximum number of modules 22 to control up to a predetermined maximumnumber of stations V. There is space in controller 2 for accepting up tofour modules 22 side-by-side in terminal area 16, thus allowing up toeight stations to be controlled. If one module 22 is installed, then upto two stations can be controlled, with two modules 22 up to fourstations can be controlled, and so on. FIG. 8 illustrates aconfiguration having two modules installed controlling four stationsrepresented by the four irrigation valves V1-V4.

Referring to FIGS. 1, 6 and 7, each station module 22 includes a casing32 having a generally rectangular base 34 secured to a tapered top 36.Base 34 and top 36 may be separable to allow a printed circuit board tobe inserted into module 22 during manufacture, with base 34 and top 36then being snapped together and held as a unit by suitable connectors38. One end of module 22 includes the two snap-in wire terminals 24 a,24 b representing the output end of module 22. The other or input end ofmodule 22 has a plug connection for allowing module 22 to be pluggedinto one set 40 of four output pins 42 on a parallel output bus incontroller 2. In each set 40 of pins 42, one pin is assigned to controlone of the terminals 24 a and 24 b, respectively, another pin is aground connection, and the remaining pin is a 5V power input to module22. See FIG. 9. Thus, when module 22 is in place and is plugged into theparallel output bus, controller 2 will activate the stations connectedto module 22 as called for by the watering program being executed bycontroller 2.

Terminal area 16 of controller 2 is provided with four slots 44 in whichmodules 22 are slidably received, with one slot 44 being provided foreach module 22. Each slot 44 is formed by the upper aligned surfaces 48of a plurality of spaced vertical walls 50 in terminal area 16, suchsurfaces 48 defining a plane against which the bottom of module 22 maybe engaged. Each slot 44 further has two spaced overhanging lips 52 oneither side thereof which are spaced from one another and are elevatedabove the upper aligned surfaces 48 of walls 50. Lips 52 are suited toslidably engage with a plurality of guide tabs 54 that jut out from thesides of modules 22 to guide modules 22 in slots 44.

As shown most clearly in FIG. 7, to insert a module 22 into one of theslots 44 in terminal area 16, module 22 is positioned as shown inphantom above slot 44 and with guide tabs 54 on modules 22 being locatedin the gaps between the spaced lips 52. Module 22 is then droppeddownwardly until the bottom thereof rests on the upper aligned surfaces48 of vertical walls 50. Module 22 is then pushed inwardly in slot 44relative to the parallel output bus until the pin set 50 on the busplugs into the connector provided therefor in the input end of module 22as shown in solid lines in FIG. 7. In this position, guide tabs 54 onmodule 22 have slid beneath lips 52 on the sides of slots 44.

The top of each module is provided with means forming a spring biasedlatch. More specifically, this latch is provided by a section 60 of thetop wall of module 22 that is cut away along its sides and rear but isjoined to module 22 at the front, in effect being supported in themanner of a cantilever. This section 60 will have a natural outwardbiasing force which tends to keep this section 60 aligned with theremaining portions of the top wall of module 22. The rear of section 60is provided with an upwardly protruding hook 62. Hook 62 is adapted toengage against the rear side of a vertical wall 64 that overlies theinner end of slot 44.

As module 22 is slid into place in a slot 44 (after it has been droppedinto place in slot 44 with guide tabs 54 ready to be pushed beneath lips52), hook 62 will be cammed down beneath wall 64 with the cut away topwall section 60 deflecting down as necessary to allow this movement.When hook 62 clears wall 64 as module 22 plugs into the pin set 40 onoutput bus, the cut away section 60 of the top wall 55 will spring backupwardly to its normal untensioned state where it is generally alignedwith the remainder of the top wall. Thus, hook 62 and cut away section60 of the top module wall form, in effect, a spring biased latch forfirmly locking module 22 in place in slot 44.

To remove any particular module from its slot 44, the user simplypresses down on the cut away section 60 of the top wall to disengagehook 62 from behind wall 64, and then pulls slightly outwardly on module22 to clear guide tabs 54 from beneath lips 54 and to unplug module 22from the output bus. Module 22 is then simply lifted up out of slot 44.Thus, the actions required to remove a module 22 are the reverse ofthose used to install module 22.

The electronic circuitry for activating the solenoid S on the valves Vis contained on the printed circuit board that is carried within eachmodule 22. Referring to FIG. 9, this circuitry comprises a transistordriver 70 for activating a TRIAC switching device 72. Each terminal 24a, 24 b is connected to its own transistor/TRIAC combination 70/72.Thus, when controller 2 determines that a particular valve V should beopened, it does so by activating the appropriate transistor 70 to closethe appropriate TRIAC 74, thus activating the solenoid of theappropriate valve.

The use of plug in, removable station modules 22 for serving as theconnection to the irrigation stations allows controller 2 to have greatversatility. If only a four station controller is needed, only twomodules 22 need be used. Thus, the user can tailor controller 2 tocontrol precisely only those numbers of stations that are required for aparticular irrigation system. In addition, modules 22 are allconveniently located within, and protected by, housing 4 of controller2. Thus, controller 2 is compact and not unduly bulky. The bottom ofcontroller housing 4 includes various ports or openings 80 for routingwires to and from terminal area 16 for connection to terminal blocks 20or station modules 22. See FIG. 4.

The Applicants have found that controller 2 will have great resistanceto lightning strikes that may induce surge currents on the stationwires. In previous controllers, the energy from such a strike will oftenbe conducted back to controller 2 along the wires connecting controller2 to the particular station affected by the strike. Since these wiresare usually connected directly to a terminal strip that is hardwired tothe main printed circuit board of controller 2, i.e. to the circuitboard having the microprocessor controller, this energy could oftendamage many of the controller's components, including themicroprocessor.

However, with modules 22 of the present invention, Applicants have foundthat much of the energy from a lightning strike will be absorbed by theelectronic circuitry within module 22 without damaging the main printedcircuit board in controller 2. Thus, while module 22 itself may bedestroyed by the lightning strike, it is a simple matter to replace thismodule with a new one. This is an easy and inexpensive task compared tothe cost of repairing or replacing the main circuit board of the entirecontroller 2.

Turning now to the mechanical mounting of controller 2 on the wall, themounting bracket 6 includes a planar surface 82 that may be screwed orin some other way fixed to the wall. A pocket receiving space 83 isformed on this mounting bracket 82 which is bounded by two spaced sidewalls 84, by a bottom wall 86 and by the planar surface 82 of bracket 6.This space 83 has a predetermined depth determined by the depth of sidewalls 84. Each side wall 84 has an outwardly protruding tab 88 on thefront side thereof spaced away from planar surface 82 by an appropriatedistance.

The rear surface of controller 2 housing has a bayonet type slotstructure 90 for receiving tabs 88 on mounting bracket 6. Basically,each tab 88 is initially received into an open rectangular portion 92 ofslot 90, and controller housing 4 can then be slid down relative tomounting bracket 6 until tabs 88 are received behind wall portions 94 ofslot 90. Thus, controller housing 4 can be removably attached to wall 5using mounting bracket 6, and can be slid onto and off of mountingbracket 6 at will.

The rear surface of controller housing 4 includes a rearwardlyprotruding pocket 96 for holding a user's or operator's manual 98. Thedepth and size of pocket 96 is sufficient to allow pocket 96 to bereceived in the pocket receiving space 83 provided on bracket 6 betweenside walls 84. Thus, when controller housing 4 is in place on mountingbracket 6, the space 83 between housing 4 and the planar surface 82 ofmounting bracket 6 is used to conveniently store the user's manual 98.See the phantom line illustration in FIG. 2.

It is a great advantage to have the user's manual located in a readilyaccessible manner on controller 2 housing. The user need not go look forthe manual in some remote space when some question arises as to theprogramming or operation of controller 2. In addition, the manualstorage is done in an out-of-the way, unobtrusive location, thusenhancing the probability that it will be used for this purpose.

Various modifications of this invention will be apparent to thoseskilled in the art. Thus, the scope of this invention is to be limitedonly by the appended claims.

What is claimed is:
 1. An irrigation controller system comprising: ahousing assembly; a microprocessor disposed in said housing assembly andprogrammable to run an irrigation schedule; a selection of stationmodules independently connectable to said microprocessor; at least twoof said station modules in said selection being interchangeable with oneanother; a plurality of slots disposed in said housing assembly, each ofsaid plurality of slots sized to receive a station module; a routinedisposed in said microprocessor for sensing a presence or absence of astation module in each of said plurality of slots; and, a routinedisposed in said microprocessor for programming said irrigation schedulebased on said sensing of a presence or absence of a station module insaid plurality of slots.
 2. An irrigation controller system according toclaim 1, further comprising: an electrical interface located at one endof each of said plurality of slots and connectable to one end a stationmodule; said electrical interface connected to a power source suitablefor energizing a solenoid connected to said station module.
 3. Anirrigation controller system according to claim 1, further comprising: alocking mechanism associated with each of said plurality of slots forsecuring a station module in each of said plurality of slots.
 4. Anirrigation controller system according to claim 3, wherein said lockingmechanism is a spring biasing member.
 5. An irrigation controller systemaccording to claim 1, further comprising: a rain switch interface.
 6. Anirrigation controller system according to claim 1, further comprising: acovering removably disposed on said housing assembly; said coveringsized to enclose said plurality of slots;
 7. An irrigation controllersystem according to claim 6, wherein said covering includes operationalcontrols mounted thereon.
 8. An irrigation controller system accordingto claim 1, further comprising: an alignment member associated with eachof said plurality of slots for aligning a position of a station modulein each of said plurality of slots.
 9. An irrigation controller systemaccording to claim 8, further comprising: a guide surface disposed oneach of said at least two station modules, said guide surface shaped tointeract with said alignment member.
 10. An irrigation controller systemaccording to claim 1, wherein said at least two station modules eachhave a generally rectangular base secured to a generally tapered top.11. An irrigation control system comprising: a base assembly; aplurality of station modules, at least two of which beinginterchangeable with each other; a microprocessor housed in said baseassembly; a plurality of slots disposed in said base assembly, each ofsaid plurality of slots shaped to receive one of said plurality ofstation modules; an electrical interface associated with each of saidplurality of slots and connectable to a station module; an electricalpathway providing an electrical connection between said microprocessorand each electrical interface; a power source disposed on said baseassembly; said power source providing energy to each electricalinterface suitable for operating a solenoid when said electricalinterface is connected to a station module.
 12. An irrigation controlsystem according to claim 11, further comprising: a power sourceproviding 24 VDC to each electrical interface.
 13. An irrigation controlsystem according to claim 11, wherein said electrical pathway is anelectrical bus.
 14. An irrigation control system according to claim 13,wherein said electrical bus is a parallel output bus.
 15. An irrigationcontrol system according to claim 11, further comprising: a routinedisposed in said microprocessor for sensing a presence or absence of astation module in said plurality of slots.
 16. An irrigation controlsystem according to claim 15, further comprising: a routine disposed insaid microprocessor for programming a watering schedule in saidmicroprocessor based on sensing a presence or absence of a stationmodule in said plurality of slots.
 17. An irrigation control systemaccording to claim 11, further comprising: a locking mechanismassociated with each of said plurality of slots for securing a stationmodule in each slot.
 18. An irrigation control system according to claim17, wherein said locking mechanism is a spring biased locking mechanism.19. An irrigation controller system comprising: a housing; a collectionof individual modules, each individual module connectible to a pluralityof watering stations; a plurality of slots disposed in said housing,each of said slots shaped to receive a portion of one of said individualmodules; at least two individual modules of said collection ofindividual modules being interchangeable with each other; amicroprocessor disposed in said housing and having an electrical pathwayto each of said plurality of slots; said microprocessor having softwarewith which to sense an insertion of a module into any of said pluralityof slots; said microprocessor having software with which to program awatering schedule based on said sensing of an insertion of a module intoany of said plurality of slots.
 20. An irrigation controller systemaccording to claim 19, further comprising: a power source disposed insaid housing for energizing said watering stations; said power sourceproviding energy to said watering stations through said electricalpathway to each of said plurality of slots.